In many low permeability oil and gas producing formations, wells are formed by drilling wellbores that curve to a generally horizontal orientation. The horizontal section of the wellbore is positioned to extend through the target formation containing oil or gas hydrocarbons. In many cases, the best production can be achieved by drilling horizontally in the direction of the minimum horizontal stress of the rock/formation and then creating propped hydraulic fractures along the horizontal section of the wellbore. However, the practical implementation of multiple transverse propped fractures along a horizontal section of the wellbore can be problematic and expensive. As a result, the number of actual transverse fractures created is usually less than the optimal number indicated by production simulation models.
With respect to current completion practices for horizontal wells, several different approaches are used. For example, some applications employ cased and cemented completions that use perforations to connect the wellbore with the surrounding formation. However, the cement can damage natural fractures, and initiation of transverse fractures from the perforations can create multiple and complex fracturing. Such fracturing creates problems with respect to placement and constriction during hydrocarbon production. Additionally, the approach requires multiple trips into the wellbore for perforating each stage which adds to the time and expense of the operation.
In another application, open hole completions are used without cement, but these types of completions provide very little control for creating multiple induced transverse fractures and often result in the formation of a single fracture across the entire horizontal section of the wellbore. In other applications, open hole packer systems and isolation devices are used to create some degree of isolation that can enable multiple stages to be created. However, the practical number of transverse fractures is limited, and the required hardware is complicated and expensive. In some applications, the hardware assemblies are prone to becoming stuck in the wellbore before being properly placed, or the systems have difficulty in holding pressure effectively.